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(#) Potentially unnecessary required feature

!!! WARNING: Potentially unnecessary required feature
   This is a warning.

Id
:   `UnnecessaryRequiredFeature`
Summary
:   Potentially unnecessary required feature
Severity
:   Warning
Category
:   Usability
Platform
:   Android
Vendor
:   Android Open Source Project
Feedback
:   https://issuetracker.google.com/issues/new?component=192708
Since
:   8.7.0 (October 2024)
Affects
:   Manifest files
Editing
:   This check runs on the fly in the IDE editor
Implementation
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/RequiredFeatureDetector.kt)
Tests
:   [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/RequiredFeatureDetectorTest.kt)

Avoid unnecessarily requiring features that may exclude your app from
being served onto devices it might otherwise support.

Consider whether your application can function adequately without
restrictive feature requirements by setting these to
`android:required="false"`. By doing so, you can increase the
availability of your app to a broader set of devices, including tablets,
laptops and cars.

!!! Tip
   This lint check has an associated quickfix available in the IDE.

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
AndroidManifest.xml:7:Warning: Consider whether this feature
(android.hardware.camera.autofocus) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.camera.autofocus" /&gt; &lt;!-- WARN 1 --&gt;
                                ---------------------------------
AndroidManifest.xml:8:Warning: Consider whether this feature
(android.hardware.camera.flash) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.camera.flash" /&gt; &lt;!-- WARN 2 --&gt;
                                -----------------------------
AndroidManifest.xml:9:Warning: Consider whether this feature
(android.hardware.location.gps) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.location.gps" /&gt; &lt;!-- WARN 3 --&gt;
                                -----------------------------
AndroidManifest.xml:10:Warning: Consider whether this feature
(android.hardware.nfc) really is required for the app to function; you
can set android:required="false" to indicate that the feature is used
but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.nfc" /&gt; &lt;!-- WARN 4 --&gt;
                                --------------------
AndroidManifest.xml:11:Warning: Consider whether this feature
(android.hardware.nfc.hce) really is required for the app to function;
you can set android:required="false" to indicate that the feature is
used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.nfc.hce" /&gt; &lt;!-- WARN 5 --&gt;
                                ------------------------
AndroidManifest.xml:12:Warning: Consider whether this feature
(android.hardware.telephony) really is required for the app to function;
you can set android:required="false" to indicate that the feature is
used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.telephony" /&gt; &lt;!-- WARN 6 --&gt;
                                --------------------------
AndroidManifest.xml:13:Warning: Consider whether this feature
(android.hardware.touchscreen) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.touchscreen" /&gt; &lt;!-- WARN 7 --&gt;
                                ----------------------------
AndroidManifest.xml:14:Warning: Consider whether this feature
(android.hardware.touchscreen.multitouch) really is required for the app
to function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.touchscreen.multitouch" /&gt; &lt;!-- WARN 8 --&gt;
                                ---------------------------------------
AndroidManifest.xml:15:Warning: Consider whether this feature
(android.hardware.screen.portrait) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.screen.portrait" /&gt; &lt;!-- WARN 9 --&gt;
                                --------------------------------
AndroidManifest.xml:16:Warning: Consider whether this feature
(android.hardware.screen.portrait) really is required for the app to
function; you can set android:required="false" to indicate that the
feature is used but not required [UnnecessaryRequiredFeature]
    &lt;uses-feature android:name="android.hardware.screen.portrait" android:required="true" /&gt; &lt;!-- WARN 10 --&gt;
                                --------------------------------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`AndroidManifest.xml`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~xml linenumbers
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.pkg"&gt;

    &lt;uses-sdk android:minSdkVersion="28" /&gt;
    &lt;uses-feature android:name="android.hardware.type.watch" /&gt; &lt;!-- OK --&gt;
    &lt;uses-feature android:name="android.hardware.camera.autofocus" android:required="false" /&gt; &lt;!-- OK --&gt;
    &lt;uses-feature android:name="android.hardware.camera.autofocus" /&gt; &lt;!-- WARN 1 --&gt;
    &lt;uses-feature android:name="android.hardware.camera.flash" /&gt; &lt;!-- WARN 2 --&gt;
    &lt;uses-feature android:name="android.hardware.location.gps" /&gt; &lt;!-- WARN 3 --&gt;
    &lt;uses-feature android:name="android.hardware.nfc" /&gt; &lt;!-- WARN 4 --&gt;
    &lt;uses-feature android:name="android.hardware.nfc.hce" /&gt; &lt;!-- WARN 5 --&gt;
    &lt;uses-feature android:name="android.hardware.telephony" /&gt; &lt;!-- WARN 6 --&gt;
    &lt;uses-feature android:name="android.hardware.touchscreen" /&gt; &lt;!-- WARN 7 --&gt;
    &lt;uses-feature android:name="android.hardware.touchscreen.multitouch" /&gt; &lt;!-- WARN 8 --&gt;
    &lt;uses-feature android:name="android.hardware.screen.portrait" /&gt; &lt;!-- WARN 9 --&gt;
    &lt;uses-feature android:name="android.hardware.screen.portrait" android:required="true" /&gt; &lt;!-- WARN 10 --&gt;

    &lt;application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" &gt;
        &lt;activity
            android:name=".BytecodeTestsActivity"
            android:label="@string/app_name" &gt;
            &lt;intent-filter&gt;
                &lt;action android:name="android.intent.action.MAIN" /&gt;

                &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
            &lt;/intent-filter&gt;
        &lt;/activity&gt;
    &lt;/application&gt;

&lt;/manifest&gt;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/RequiredFeatureDetectorTest.kt)
for the unit tests for this check to see additional scenarios.

(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Adding the suppression attribute
  `tools:ignore="UnnecessaryRequiredFeature"` on the problematic XML
  element (or one of its enclosing elements). You may also need to add
  the following namespace declaration on the root element in the XML
  file if it's not already there:
  `xmlns:tools="http://schemas.android.com/tools"`.

  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;manifest xmlns:tools="http://schemas.android.com/tools"&gt;
      ...
      &lt;uses-feature tools:ignore="UnnecessaryRequiredFeature" .../&gt;
    ...
  &lt;/manifest&gt;
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="UnnecessaryRequiredFeature" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'UnnecessaryRequiredFeature'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore UnnecessaryRequiredFeature ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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